1. Field of the Invention
The present invention relates in general to a method of supplying electric components and an electric-component mounting system arranged to mount the electric components, and more particularly to improvements in the accuracy with which a component-mounting unit of the electric-component mounting system receives the electric components from a feeder of a component-supplying device of the system.
2. Discussion of Related Art
One example of an electric-component mounting system is provided with a component-supplying device including a plurality of feeders each operable to feed a succession of electric components (typically, electronic components), and a component-mounting device including a suction nozzle operable to receive the electric components from a component-supply portion of a selected one of the feeders. The plurality of feeders are arranged in a direction perpendicular to the direction of feeding of the electric components by each feeder. Where the component-mounting device includes a plurality of suction nozzles, a plurality of electric components can be simultaneously received and held by suction by the respective suction nozzles, so that the component-mounting device can be supplied with the electric components with improved efficiency. For instance, the suction nozzles are fixedly disposed on a single movable member such that the suction nozzles are equally spaced from each other in the direction of arrangement of the feeders, by a spacing interval equal to a multiple of a spacing interval of the feeders. The spacing interval of the suction nozzles is equal to a distance between the axes of the adjacent suction nozzles, while the spacing interval of the feeders is equal to a distance between the component-supply portions of the adjacent feeders. In this arrangement, the plurality of suction nozzles can be concurrently aligned with the component-supply portions of the respective feeders, so that the electric components can be simultaneously held by suction by the respective suction nozzles located at the positions aligned with the component-supply portions.
In some electric-component mounting systems, the component-supply portions of the plurality of feeders are not equally spaced apart from each other in the direction of arrangement of the feeders. In these-systems, the plurality of suction nozzles of the component-mounting device cannot be simultaneously aligned with the component-supply portions of the respective feeders, so that the electric components fed to the component-supply portions cannot be simultaneously received by the respective suction nozzles. Further, the suction nozzles may be misaligned with respect to the respective component-supply portions of the feeders, due to variations in the distance between the axes of the adjacent suction nozzles and the distance between the component-supply portions of the adjacent feeders, which variations may arise from errors in the manufacture and assembling of the suction nozzles and the feeders. In this case, the electric components supplied from the feeders cannot be held by suction by the respective suction nozzles, or the electric components held by the suction nozzles cannot be accurately centered with respect to the sucking surface of each suction nozzle, leading to instability of holding of the electric components by the suction nozzles.